英语题there are five pairs to choose from ,but i am at a loss which to buy

问题描述:

英语题there are five pairs to choose from ,but i am at a loss which to buy
there are five pairs______,but i'm at a loss which to buy.
choose from
为什么不能选for choosing

to choose表示一个动作
for choosing表示状态
所以不能选
to do为不定式